#rect {
    position: fixed;
    outline: 1px solid #000;
}

#finish {
    width: 16px;
    height: 16px;
    background-color: #f00;
    border-radius: 8px;
    position: absolute;
    right: 0;
    bottom: 0;
    cursor: pointer;
}

#finish:hover {
    background-color: #0000;
}
